Nice, thick fabric for shirt, blouse and dress is from rural areas of Kerala. Kerala is known for both finest fabric as well as thick fabric. The finer ones are used for sarees and dresses while the thick ones are for tapestry.
Kerala dyeing plants have to compulsorily use VAT dyes (which are declared as environment friendly in international market) and have to treat water that is used for dyeing before discharging it to main drainage system. So you are doing good to environment when you where clothes dyed in Kerala.